Chronic Pain Changes Your Brain
Aug 06, 2018
Brain health isn't a topic discussed often enough, particularly within the medical community. On the bright side, the topics of mental health and access to mental health services have come to light in the last few years. But, the aging brain is often left out of the conversation.
There are many unanswered questions about the decline in brain health with aging. The medical profession is starting to observe the differences in adults who experience brain atrophy and those who don’t. So, we're gaining some clarity. But, there's still so much we don't know.
The research identified some clear patterns in those who receive a diagnosis of dementia. But, keep in mind that patterns don't always give a clear cause. We know fall risk increases with increasing mental decline. We know poor mental health increases the risk of developing dementia. We know a connection exists between muscle weakness and dementia. What isn't as clear is why.
I've studied these connections between physical and mental health in my five short years as a geriatric physical therapist. I am fortunate to have fallen into a profession where I work with older adults while still in my 30s. This work provides me with a unique perspective into my future and the future of my loved ones. It leaves me in a unique position to see the puzzle that leads to a decline in brain health. I do my best to put the pieces together to mitigate or even undo some of the damage.
Unfortunately, I'm not often referred to patients and their families until they are in the later stages of mental or physical decline. This leaves me tracing back to form a clear picture of what that person was like before they had dementia. Over time, I've caught on to patterns that guided my research. These are some of the observations I've made that research justifies.
The Connection Between Chronic Pain and Brain Health
One recent area of study is the impact of chronic pain on the aging brain. Up to 50% of older adults experience chronic pain, making pain an area of high impact on topics in aging.
Chronic pain has many levels of influence on brain health, including changing the brain itself. For example, chronic pain increases the incidence of depression and anxiety. In addition, the use of medications for pain management impairs brain function. These factors make studying the connection between chronic pain and brain health complicated.
So, let’s explore these complexities further. By unraveling the connections between pain and brain health we can shine a light on the issues. As a therapist, I aim to open up the discussion on brain health and aging.
And most importantly, knowledge is power. We'll show you how to use this information to age well.
First, Sometimes Pain is Normal…
Whether we want to believe it or not, acute pain serves a useful purpose to our body. No one likes to be in pain, but acute pain is a signal that an area of our body needs attention. Pain is your brain's way of prioritizing actions you need to take to keep yourself safe.
For example, if you sprain your ankle by stepping off the curb the wrong way while crossing a street, you experience pain. Your brain decides this ankle sprain is now the biggest threat to your survival. You can't walk around and perform your daily functions with an ankle injury after all. Your brain will let you know you're injured using a pain signal pathway. Feeling pain causes you to take the appropriate action to address the issue. The pain you feel keeps you from walking, which allows the damaged tissue in your ankle to heal. As your ankle heals, the pain resolves.
It's important to note that pain is not coming from your ankle itself. Pain is an output of the brain, but this doesn't mean you are imagining the pain! The pain is real, so don't confuse this with hearing unresolved pain is "all in your head".
The above story of the ankle sprain is an example of how acute pain is a benefit to us. Chronic pain is a different story though. More complicated than tissue damage equals immediate pain. To explain this further, let’s take a closer look at the nervous system....
A Quick Primer on Your Nervous System
Your nervous system consists of one set of nerves that run from tissues to the brain that carry sensory information (sensory nerves). Another set of nerves run from the brain to your muscles (motor nerves). Your brain is also part of your nervous system (and we can all agree, your brain is pretty important).
Sensory nerves take information about touch, pressure, temperature, and pain. This information allows your brain to determine what's important enough for action. Put your hand too close to a hot stovetop and react by pulling your hand away from the heat before you even realized what was happening? Thank your sensory nerves and your brain. These nerves relay vital information about your environment to the brain, protecting you in your world.
There might be times when your brain determines an injury is not the main priority at the moment. So it has the ability to delay the pain response to allow you to address a more pressing issue. For example, what if you sprain your ankle while crossing a street and look up to see a bus coming at you? You forget about the ankle so you can get out of the way of the bus! After all that adrenaline, you likely won’t feel the ankle pain for a few hours after all is calm.
Simple. Your brain prioritized your life over the ankle injury. This is a perfect example of your brain prioritizing. In this case, the ankle damage can wait until your life is out of harm's way.
We can compare the pain cycle to an alarm system. In the case of an acute ankle injury, the alarm is going off for a reason. But chronic pain is a completely different picture. It persists even after the injury heals, or might have started when there wasn't an injury at all.
With chronic pain, the alarm continues to go off long after there is no longer the threat of tissue damage. Over time, chronic pain impacts different areas of our brain than acute pain. For example, the research found in cases of chronic pain the area of the body in pain starts to take up more physical space in the brain. Furthermore, pain receptors in that area of the body increase in number AND become more sensitive to stress hormones. Which means if you have chronic pain, stress is not your friend.
All these changes combined lower your pain threshold in that area of the body. This makes something that would normally not be painful cause an awful lot of pain. The good news is this recent discovery led to a wider variety of options for chronic pain treatment (as we will discuss in a moment).
So, now that we have the basic information about pain response covered let’s take a closer look at what research on chronic pain and brain health found...
Chronic Pain Changes the Brain’s Resting State
Under normal circumstances, your brain has an organized pattern of activity during the resting state. Studies have shown this pattern is disrupted in autism, Alzheimer’s disease, depression, and ADHD. Research has found chronic pain alters the resting brain state in a similar manner.
And remember, pain also increases depression, anxiety, and inhibits sleep. This further compounds the resting state of the brain. These disruptions contribute to altered mental status over time in those with chronic pain.
Chronic Pain Impacts Emotional and Memory Systems in the Brain
Over time, chronic pain becomes a part of the emotional and memory systems of the central nervous system. This leads to a learned fear of movement. The brain learns that movement causes pain, making you not want to move. If you've experienced either short term or long term pain, you know how emotional the experience can become. The impact on both of these systems over time can create permanent damage in the brain.
Chronic Pain Impairs Attention
Acute pain, which is well studied, disrupts thinking. So we can only imagine the impact of chronic pain on our thought patterns. Attention decreases in cases of chronic pain because pain takes over other areas of the brain. This occupation of working memory areas of the brain leads to loss of attention for other tasks. This loss of attention can even occur with tasks not related to pain or movement at all.
Chronic Pain Changes Your Brain's Control Of Your Body
The brain's control over your physical performance declines with increasing levels of pain. Your brain is the mediator of pain and physical performance. Which means increasing pain leads to worsening physical performance over time. Increasing pain severity impacts your body's position sense, mental flexibility, and manual dexterity.
Chronic Pain Increases Loss of Brain Volume
Loss of brain volume occurs in older adults with disrupted sleep, depression, and anxiety. Chronic pain contributes to a loss in brain volume as well. But brain tissue loss seen in chronic pain is different than patterns seen in older adults with chronic depression or anxiety.
To further complicate this aspect of brain health, depression and anxiety increase the risk of dementia. And we also know that chronic pain increases the incidence of depression and anxiety (see how this is becoming a puzzle now?). Chronic pain impacts the brain on its own, but also through its' secondary effects.
No discussion of chronic pain and the brain would be complete without mentioning pain medications. Medications are a topic we can discuss for hours on end, but we will briefly mention them. Research has found the opioid medications often prescribed for pain are connected with a decline in brain health. And further complicating the issue, older adults respond differently to strong pain medications. This can make changes in the brain more difficult to identify and link to the use of pain medication.
So What Can You Do?
We don’t want to leave you with this picture of doom and gloom! Now that we covered the latest research, let’s talk about what you can do to improve both your levels of pain and boost your brain health.
We hope we cleared up some of the mystery surrounding the connections between brain health, aging, and movement.